﻿m_list = []

while True:
    if len(m_list) == 2:
        notice = '   {}\n'.format(str(m_list[0]))
        notice += ' + {}\n'.format(str(m_list[1]))
        notice += ' = {}\n'.format(str(sum(m_list)))
        print(notice)
        break
    else:
        m_item = input('请开始输入:')
        m_list.append(float(m_item))